Methods of appropriately supplying oil (refrigerator oil) to a plurality of compressors include use of a refrigerating device described in Japanese Patent No. 3937884 (Patent Literature 1), for example. This refrigerating device is constructed by a refrigerating cycle in which a plurality of compressors connected in parallel, a condenser, a decompressor, an evaporator, and an accumulator are serially connected, provides an oil recovering circuit that recovers excess refrigerator oil in the compressor into the accumulator, holds the refrigerator oil circulating through the refrigerating cycle in the accumulator and provides an operation controller that stops an operation of a target compressor when an oil recovering operation for recovering the refrigerator oil in the compressor into the accumulator. Alternatively, an oil return circuit that supplies the refrigerator oil in the accumulator to the compressor is provided.
On the other hand, in the refrigerator, it is demanded to increase in refrigerating capacity, and it has been considered to increase in capacity by combining a plurality of existing refrigerators in order to realize to increase in capacity easily and inexpensively.
As means for satisfying the above demand, as in illustrated in Japanese Patent No. 3930654 (Patent Literature 2), a use of a multiple-unit refrigerator provided with one or a plurality of compressors for one outdoor unit in a form in which a plurality of outdoor units are connected in parallel by piping between the units, extending from the outdoor units, has been considered. Moreover, an oil tank that stores oil separated by an oil separator from a high-pressure gas refrigerant discharged from the compressor is made to flow through each outdoor unit in order to equalize oil.